5. Halo 3
What's better than being a genetically engineered super soldier blowing up alien monsters, driving tanks, flying space ships, and jumping chasm gaps in a warthog jeep? Doing all that with a buddy. Hey, did we make this joke before? Halo 3 is an intense single player experience, but when you throw in a second (or third, or fourth) player, bump the difficulty to Legendary, and pop open a few cans of [Insert name of popular beverage here], you’ve got yourself the formula for a killer game night. Halo does co-op right. The campaign gives you vehicles with multiple seats, difficulty options that are almost impossible to manage on your own, and makes you wish your friend sitting next to you could jump in and help. And then it lets them.